MXPA98006658A - Composition of aqueous coating to protect finishes and process for the production of the mi - Google Patents

Abstract

The present invention relates to a coating composition that includes a combination of polyols containing hydroxyl group and blocked polyisocyanate crosslinking agents, which preferably is dried in a dusty manner on the surface to be coated and, after protection, provides coatings having a high resistance to water, chemicals and solvents, in particular on metal substrates, and a process for the production of the coating composition

Description

COMPOSITION OF AQUEOUS COATING TO PROTECT FINISHES AND PROCESS FOR THE PRODUCTION OF THE SAME Field of the Invention The invention relates to an aqueous coating composition including polyols containing hydroxyl group and crosslinking agents of blocked polyisocyanate, which is preferably dried in a powdery manner on the surface to be coated and, after protection, provides coatings having high resistance to water, chemicals and solvents, particularly on metal substrates. The invention also relates to a process for the production of the coating composition.

Background of the Invention Aqueous polyurethane dispersions are known (cf Houben-Weyl, Methoden der organischen Chemie [Organic Chemistry Methods], Fourth Edition, vol.E20, p.1659 (1987)). However, non-reactive polyurethanes have a number of REF. 28117 weaknesses with respect to the high quality profile required by, for example, automotive finishing applications. These weaknesses are mainly due to the insufficient cross-linking between the macromolecules that form the film, which manifest themselves in the reduced resistance to water, chemicals and solvents and in the low-grade mechanical properties. Newer post-curing coating systems, which are obtained, for example, by combining isocyanate reactive resins with blocked polyisocyanate crosslinking agents, provide better properties (cf. JW Rosthauser, K. Nachtkamp in Advances in Urethane Science and Technology , KC Frisch and D. Klempner, editors, Vol. 10, pp. 121-162 (1987)).

Resins and dispersions of polyurethane, polyepoxy, polyester or polyacrylate, which are crosslinkable by means of hydroxyl groups are used as resins. The crosslinking agents are blocked polyisocyanates, which optionally have been modified hydrophilically. Such systems are known from, for example, DE-A 4,213,527, EP-A 581 211, EP-A 427 028, US 4,543,144, DE-A 3,345,448 and DE-A 2, 829,648.

The systems which are considered for painting and coating applications have the property of demonstrating good properties that form the film, even at room temperature. If this property is deficient, films with a poor overall quality profile result. This includes, in particular, poor coating flow and low gloss. In some examples, the formation of the film is also promoted by the addition of solvents and coalescing agents.

The application of the powder coatings from the aqueous phase is described, for example, in DE-A 19,523,084, DE-A 19,540,977, EP-A 652,264, EP-A 714,958 and WO 96/37561. A disadvantage of these applications is that during the production the binder is expelled by a grinding operation, which is very laborious and expensive. In addition, the grinding operation sets limits on the fineness of the powders, and this is frequently remarkable as resistance to inadequate sedimentation in the resultant powder suspensions.

Unexpectedly it has now been found that solvent-free coating dispersions, which are based on selected polyhydroxyl components and blocked, hot-dried, powder-dried polyisocyanates, can be obtained successfully and economically. The resulting products are coating compositions useful for processing as packaged products and making it possible to produce coatings having particularly high grade properties. It is remarkable that the coating system does not contain, or only very small amounts of, organic cosolvents and that coating films are obtained which have very good flow properties and a high gloss, which are highly resistant to water, solvents and chemicals .

A further advantage is the ease of processing coatings produced according to the invention in existing wet coating installations despite the fact that the binders are dried in a dusty manner. With good flow. , slimming films are obtained which is the case with conventional powder coating, and jet washing the equipment and boxes simplifies the cleaning operation in comparison with those of the powder coating. Also the cleaning effort is less than is the case with finishes containing solvent because of the absence of film formation or, compared with coatings of 2 packs, crosslinking at room temperature.

The invention overcomes the disadvantages of the known methods for making systems having water. The production of conventional known water coating systems which form films, even at room temperature, either requires considerable amounts of nonionic emulsifiers, or the systems contain high levels of carboxyl groups, which are neutralized with ammonia or amines ( ionic emulsifiers). This frequently results in the formation of microbubbles during the production and application of the coatings, and in addition it is also the reason for the often poor water resistance of the corresponding coating films. Furthermore, these coating systems often have only one narrow application window (the temperature range and the relative atmospheric humidity at which the application is possible) and have a pronounced tendency to form bubbles (boiling). The window is markedly more favorable in the case of binders which are preferably dried in a dusty manner. The surface properties are less dependent on climatic conditions (temperature, relative atmospheric humidity) during application. In addition, higher film thicknesses can be achieved without the occurrence of boiling due to the evaporation of water.

Brief Description of the Invention The present invention provides an aqueous coating composition which is produced by combining: A) a polyol component based on polyester polyols, polyacrylate polyols and / or polyester polyacrylate polyols having a hydroxyl group content of 1.0 to 6.0% by weight, a carboxyl group content of 0 to 1.5% by weight , a weight average molecular weight of 2000 to 50000 and a glass transition temperature that is greater than or equal to 30 ° C; B) a polysiocyanate component having blocked isocyanate groups based on (cyclo) aliphatic polyisocyanates having a blocked isocyanate group content of 10.0 to 25.0% by weight, with water to form an aqueous dispersion. The invention is also directed to a method of making the composition and a method of using the composition.

Detailed description of the invention The present invention provides an aqueous coating composition, which is dried in a dusty manner and is produced by combining: A) a polyol component based on polyester polyols, polyacrylate polyols and / or polyester polyacrylate polyols having a hydroxyl group content of 1.0 to 6.0% by weight, a carboxyl group content of 0 to 1.5% by weight , a weight average molecular weight of 2000 to 50000 and a glass transition temperature greater than or equal to 30 ° C, B) a polysiocyanate component having blocked isocyanate groups and based on (cyclo) aliphatic polyisocyanates having a blocked isocyanate group content of 10.0 to 25.0% by weight, C) optionally additional polyfunctional polyols, D) optionally additional crosslinking substances, E) optionally external emulsifiers, and F) optionally conventional additives such as, for example, neutralizing agents, catalysts, auxiliary substances, and / or additives such as degassing agents, flow promoters, radical interceptors, antioxidants and / or UV ultraviolet light absorbers, thickeners, small quantities of solvents and biocides, with water to form an aqueous dispersion. The dispersion can be prepared either by a direct dispersion process or by a phase inversion process, preferably by means of a dispersion device having a dispersion powder related to the volume of 1x10 to 9.8x10000 W / cm3.

The composition has a diameter of average dispersion particle size from 0.05 to 10 μm, preferably 0. 1 to 5 μm, more preferably approximately 0.15 to 2.5 μm and more preferably 0.2 to 1.5 μm and preferably dried in a dusty manner.

The present invention also provides a method for making an aqueous coating composition that is dried in a powdery manner by combining: A) a polyol component based on polyester polyols, polyacrylate polyols and / or polyester polyacrylate polyols having a hydroxyl group content of 1.0 to 6.0% by weight, a carboxyl group content of 0 to 1.5% by weight , a weight average molecular weight of 2000 to 50000 and a glass transition temperature that is greater than or equal to 30 ° C, B) a polyisocyanate component having blocked isocyanate groups and based on (cyclo) aliphatic polyisocyanates having a blocked isocyanate group content of 10.0 to 25.0% by weight, C) optionally, additional polyfunctional polyols, D) optionally, additional crosslinking substances. optionally, external emulsifiers and F) optionally, conventional additives such as, for example, neutralizing agents, catalysts, auxiliary substances, and / or additives such as, degassing agents, flow promoters, radical interceptors, antioxidants and / or UV ultraviolet absorbers, thickeners , small amounts of solvents and biocides, with water to form an aqueous dispersion. The dispersion can be prepared either by a direct dispersion process or by a phase inversion process, preferably by means of a dispersion device having a dispersion powder related to the volume of 1x10 to 9.8x10000 W / cm3.

Dispersion devices which have a dispersion powder related to high volume, for example, pressure relief homogenization nozzles, can be used to produce the dispersions of the invention by dispersion processes.

Dispersion machines are known, for example, from Formation of Emulsions, in P. Beche, Encyclopedia of Emulsion Technology, Vol. 1, New YorK, Basle, Decker 1983, but to date they have not been used to produce aqueous dispersions, which dry in a dusty way. The dust range of the dispersing machine according to the invention is from 1x10 to 9.8x10000 W / cm3, preferably 1x10 to 1x10000 W / cm3, preferably 1x10 to 1x1000 W / cm3.

The choice of the dispersion machine may depend on the amount of dust related to the volume of the dispersion machine. Dispersion machines having high volume related powder, for example high pressure homogenizers, are necessary to produce finely divided dispersions (approximately 1 μm particle diameter). Such finely divided dispersions are not easily producible in rotor / stator type machines. The jet disperser described in EP-A 0,101,007 has a special pressure relief type nozzle, which achieves an efficiency which is substantially greater than that of the high pressure homogenizers. The particle size distributors which in the high pressure homogenizer require 200 bar pressure are obtained at such low homogenization pressure as 50 bar in the jet disperser.

Particularly advantageously finely divided dispersions can be produced in both continuous and batch operation, using the jet disperser as the dispersing device.

According to the invention, the aqueous dispersion can also be converted by phase inversion from a water-in-oil emulsion to an oil-in-water emulsion.

The aqueous powder coating compositions of the invention can be used in the protection of the finishing applications on any of the heat resistant substrates, for example, as a clear coating or a pigmented coating to produce one layer and multilayer finishes, for example, in the automotive sector.

The polyol component A) of the aqueous coating includes: a) from 0 to 100 parts by weight of a polyester component comprising at least one polyester polyol having a hydroxyl value from 20 to 240 mg KOH / g at an acid value of < 12 mg KOH / g and a vitreous transition temperature from -40 to +100 ° C, b) from 0 to 15 parts by weight of an olefinically unsaturated ester component comprising at least one di (cyclo) alkyl ester of maleic acid having 1 to 12 carbon atoms in the radical (cycle) alkyl, c) from 0 to 70 parts by weight of (cyclo) alkyl esters of acrylic and / or methacrylic acid having 1 to 18 carbon atoms in the (cyclo) alkyl radical, d) from 0 to 50 parts by weight of monomers unsaturated olefinically aromatic, e) from 0 to 50 parts by weight of hydroxyalkyl esters of acrylic and / or methacrylic acid having 2 to 6 carbon atoms in the hydroxyalkyl radical, and / or reaction products thereof with e-caprolactone having a weight maximum molecular weight of 500, as well as addition products of acrylic and / or methacrylic acid and monoepoxy compounds, which can also be generated in situ during free radical polymerization, f) from 0 to 5 parts by weight of olefinically unsaturated carboxylic acids, and g) from 0 to 30 parts by weight of additional olefinically copolymerizable unsaturated compounds; where the sum of the parts by weight of components a) to g) is 100.

The polyol component A) has a hydroxyl group content of 1 to 6% by weight, preferably 1.5 to 5.5% by weight, and more preferably 2 to 5% by weight. The carboxyl group content is about 0 to 1.5% by weight, preferably 0.1 to 1.4% by weight, and more preferably 0.2 to 1.3% by weight. The molecular weight determinable by gel permeation chromatography (weight average, polystyrene standard) is about 2000 to 50000, preferably 2500 to 40000 and more preferably 3000 to 35000. The glass transition temperature measured by differential thermal analysis (DTA) is approximately greater than or equal to 30 ° C, preferably about 30 to 100 ° C and more preferably about 30 to 80 ° C.

The polyol component A) preferably includes: a) from 0 to 60 parts by weight of a polyester component comprising at least one polyester polyol having a hydroxyl value from 30 to 200 mg KOH / g to an acid value of < 10 mg KOH / g and a vitreous transition temperature from -30 to +70 ° C, b) from 0 to 12.5 parts by weight of an olefinically unsaturated ester component comprising at least one di (cyclo) alkyl ester of maleic acid having 1 to 6 carbon atoms in the (cyclo) alkyl radical, c) from 5 to 65 parts by weight of (cyclo) alkyl esters of acrylic and / or methacrylic acid having 1 to 12 carbon atoms in the (cyclo) alkyl radical, d) from 0 to 45 parts by weight of styrene, methylstyrene and / or vinyl toluene, e) from 5 to 45 parts by weight of hydroxyalkyl esters of acrylic and / or methacrylic acid having 2 to 4 carbon atoms in the hydroxyalkyl radical, and / or reaction products thereof with e-caprolactone having a weight maximum molecular weight of 500, as well as addition products of acrylic and / or methacrylic acid and monoepoxy compounds, which can also be generated in situ during free radical polymerization, f) from 0 to 4 parts by weight of acrylic acid, methacrylic acid, maleic acid, fumaric acid and / or half esters of maleic or fumaric acid having 1 to 8 carbon atoms in the alcohol radical, g) from 0 to 25. parts by weight of additional olefinically copolymerizable unsaturated compounds; where the sum of the parts by weight of components a) to g) is 100.

Component A) most preferably includes: a) from 0 to 40 parts by weight of a polyester component comprising at least one polyester polyol having a hydroxyl value from 40 to 160 mg KOH / g at an acid value of < 8 mg KOH / g and a vitreous transition temperature from -30 to +60 ° C, b) from 1 to 10 parts by weight of dimethyl ester of maleic acid, diethyl ester of maleic acid, dibutyl ester of maleic acid or mixtures of the rear monomers, c) from 10 to 60 parts by weight of (cyclo) alkyl esters of acrylic and / or methacrylic acid having 1 to 9 carbon atoms in the (cyclo) alkyl radical, d) from 5 to 45 parts by weight of styrene , e) from 10 to 42.5 parts by weight of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate and / or hydroxybutyl methacrylate and f) from 0.5 to 4 parts by weight of acrylic acid and / or methacrylic acid, where the sum of components a) to f) is 100.

The polyester component a) of the polyol component A contains at least one hydroxy functional polyester having a hydroxyl value of from about 20 to about 240 mg KOH / g, preferably from about 30 to about 200 mg KOH / g and most preferably from about 40 to about 160 mg KOH / g. The acid value is less than about 12 mg KOH7g, preferably less than 10 mg KOH / g and more preferably less than about 8 mg KOH / g. The vitreous transition temperature of the polyester component a) is about -40 to +100 ° C, preferably -30 to +80 ° C and more preferably -30 to +60 ° C. The molecular weight of the polyester polyols, which is calculated from the stoichiometry of the starting materials used, is about 460 to 11300 g / mol, preferably about 570 to 7500 g / mol and more preferably preferably about 700 to 5700 g / mol. A total of 6 groups of monomer constituents can be used in the preparation of the hydroxy functional polyesters: 1) (cyclo) alkane diols (ie, dihydric alcohols having hydroxyl groups attached (cyclo) aliphatically) within the molecular weight range of 62 to 286 such as, for example, ethanediol, 1,2- and 1, 3-propanediol, 1,2-, 1,3- and 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,2- and 1,4-cyclohexanediol , 2-ethyl-2-butylpropanediol, ether containing oxygen diols such as, for example, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol or polybutylene glycol of a maximum molecular weight of about 2000, preferably about 1000 and more preferably about 500. The reaction products of the aforementioned diols with e-caprolactone can also be used as diols, 2) trihydric and higher alcohols within the molecular weight range of 92 to 254 such as, for example, glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol and sorbitol, reaction products of the subsequent alcohols with ethylene oxide and / or propylene oxide or with e-caprolactone up to a maximum molecular weight of about 2000, more preferably about 1000, 3) monoalcohols such as, for example, ethanol, 1- and 2-propanol, 1- and 2-butanol, 1-hexanol, cyclohexanol and benzyl alcohol, reaction products of the subsequent alcohols with ethylene oxide and / or propylene oxide or with e-caprolactone up to a maximum molecular weight of about 2000, preferably about 1000 and more preferably about 500, 4) dicarboxylic acids within the molecular weight range from 116 to about 600 and / or anhydrides thereof, such as, for example. phthalic acid, phthalic anhydride, isophthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, maleic anhydride, fumaric acid, succinic acid, succinic anhydride, adipic acid, dodecanedioic acid, hydrogenated dimer fatty acids. ) higher functional carboxylic acids or anhydrides thereof with, for example, trimellitic acid and trimellitic anhydride, and 6) monocarboxylic acids such as, for example, benzoic acid, cyclohexanecarboxylic acid, 2-ethylhexanoic acid, hexanoic acid, octanoic acid, decanoic acid, dodecanoic acid, natural and synthetic fatty acids.

Any of the mixtures of monomer constituents 1) to 6) can be used in the preparation of the component. of polyester a) of the polyol component A, with the proviso that they are selected in such a way that the resulting polyesters have both OH values within the range of 20 to 240 mg KOH / g at acid values of < 12 mg KOH / g and glass transition temperatures from -40 to +100 ° C.

This condition is met when an appropriate proportion of "softening" monomer constituents, which produce approximately a decrease in vitreous transition temperature of the polyesters, to "hardening" monomers, which produce an increase in the transition temperature. vitrea, it is used in the preparation of polyesters.

The "softening" monomer constituents are, for example, aliphatic diols such as, for example, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol, or aliphatic dicarboxylic acids such as, for example, , adipic acid or dodecanedioic acid.

The "monomer" monomer constituents are, for example, cyclic aromatic dicarboxylic acids such as, for example, phthalic acid, isophthalic acid and terephthalic acid, or diols such as, for example, 1,4-cyclohexanediol, , 4-cyclohexanedimethanol or neopentyl glycol.

The polyester component a) is prepared in a known manner such as those methods described in detail in "Ullmanns Encyclopédie der der technischen Chemie" [Ullmann's Encyclopaedia of Industrial Chemistry], Verlag Chemie Weinheim, Fourth Edition (1980), Vol. 19, pp. 61 et sec., Or in H. Wagner and H.F. Sarx, "Lackkunstharze" [Synthetic Resins for Coatings], cari Hanser Verlag, Munich (1971), p. 86 to 152, for example. The esterification optionally takes place in the presence of a catalytic amount of a conventional esterification catalyst such as, for example, acids such as, for example, p-toluenesulfonic acid, bases such as, for example, lithium hydroxide, or transition metal compounds such as, for example, titanium tetrabutylate, at about 80 to 260 ° C, preferably 100 to 240 ° C.

The esterification reaction is carried out until the desired values for the hydroxyl value and the acid value are reached. The molecular weight of the polyester polyols can be calculated from the stoichiometry of the starting materials (taking into account the hydroxyl values and resulting acid values).

Component b) of the polyol component A comprises at least one di (cyclo) alkyl ester of maleic acid having 1 to 12, preferably 1 to 8 and more preferably 1 to 4 carbon atoms in the radical ( cycle) alkyl. For example, maleic acid dimethyl ester, maleic acid diethyl ester, maleic di-n-butyl ester, maleic acid di-2-ethylhexyl ester, di-n-decyl ester of maleic acid are suitable. maleic acid, di-n-dodecyl ester of maleic acid and dicyclohexyl ester of maleic acid.

Component c) of the polyol component A comprises at least one ester of (cyclo) alkyl of acrylic and / or methacrylic acid having 1 to 18, preferably 1 to 12 and more preferably 1 to 9 carbon atoms in the radical (cyclo) alkyl, such as, for example, methyl (meta) acrylate, ethyl (meta) acrylate, propyl (meta) acrylate, (meta) isopropyl acrylate, n-butyl (meta) acrylate, (meta) isobutyl acrylate, tert-butyl (meta) acrylate, cyclohexyl (meta) acrylate, 2-ethylhexyl (meta) acrylate, (meta) isobornyl acrylate, 3,3,5-tri-methylcyclohexyl (meta) acrylate, stearyl (meta) acrylate and benzyl (meta) acrylate.

Component d) of the polyol component A comprises at least one olefinically aromatic unsaturated monomer such as, for example, styrene, e-methylstyrene and vinyl toluene. Styrene is preferred.

The component e) of the polyol component A comprises at least one hydroxyalkyl ester of asrylic and / or methacrylic acid having 2 to 6 carbon atoms in the hydroxyalkyl radical, and / or reaction products thereof with e-caprolactone which it has a maximum molecular weight of 500, as well as addition products of acrylic and / or methacrylic acid and monoepoxy compounds, which can also be generated in situ during the free radical polymerization. For example, hydroxyethyl (meta) acrylate, hydroxypropyl (meta) acrylate (mixture of isomer that increases from the addition of propylene oxide to (meta) acrylic acid), hydroxybutyl (metha) acrylate, and reaction of the subsequent monomers with e-caprolactone up to a maximum molecular weight of 500. The term "hydroxyalkyl esters" should therefore also encompass radicals having ester groups, as it increases as a result of the addition of e-caprolactone to esters of simple hydroxyalkyl. The reaction products of acrylic and / or methacrylic acid with monoepoxy compounds, which can additionally also carry OH groups, should also be contemplated as "(meta) acrylic" uyl hydroxyalkyl esters and are therefore equally suitable as monomers e). Examples of suitable monoepoxides are ™ Cardura ElO (Shell), 2-ethylhexylglycidyl ether and glycidol (1,2-epoxy-3-propanol). Subsequent reaction products can also be generated in situ under the reaction conditions of the free radical polymerization.

The component f) of the polyol component A) comprises at least one olefinically unsaturated carboxylic acid such as, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, half esters of maleic acid and / or fumaric acid having 1 to 18 carbon atoms in the alcohol radical, with acrylic acid and methacrylic acid being preferred.

The component g) of the polyol component A) comprises olefinically copolymerizable unsaturated compounds, which are different from the classes of compounds of the components a) to f), such as, for example, the α-olefins such as, for example, , 1-octene or 1-decene; vinyl esters such as, for example, vinyl acetate, vinyl propionate, vinyl butyrate, VeoVa ™ 9 and VeoVa ™ 10, from Shell; other vinyl compounds such as, for example, N-vinyl pyrrolidone, N-vinyl caprolactam and N-vinyl carbazole.

The polyol component A) is prepared by free-radical polymerization of components b) to g) either in an inert organic solvent without a solvent. Component a), if necessary, is introduced first, or however, it can be used as a mixture with the monomer components b) to g) in the free radical polymerization. However, it is also possible to add component a) to the polymer which has resulted from the polymerization of components b) to g). Any of the mixtures within the aforementioned quantitative limits in each case can be used as working materials a) to g) when preparing the polyol component A), with the proviso that they are selected in such a way that the polyol binders resulting have hydroxyl values and glass transition temperatures within the ranges mentioned above.

Subsequent conditions which are essential for the polyols usable according to the invention are met when an appropriate proportion of "softening" monomers which produce approximately up to a decrease in vitreous transition temperature, to "hardening" monomers which They produce approximately an increase in the glass transition temperature used in the preparation of the sopolymers.

The "softening" monomers are, for example, the alkyl esters of acrylic acid such as, for example, ethyl acrylate, n-butyl acrylate, isobutyl acrylate and 2-ethylhexyl acrylate.

"Hardening" monomers are, for example, short chain (cyclo) alkyl esters of methacrylic acid, such as, for example, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, tertiary methacrylate. -butyl, cyclohexyl methacrylate, neopentyl methacrylate, isobornyl methacrylate and 3, 3, 5-trimethylcyclohexyl methacrylate; vinyl aromatics such as, for example, styrene, vinyl toluene and a-methyl styrene. Other softening and hardening monomers can be identified with routine experimentation.

Suitable initiators for carrying out the free radical polymerization are conventional radical initiators such as the aliphatic azo compounds, for example, the nitrile of azodiisobutyric acid, azo-bis-2-methylvaleronitrile, nitrile of 1,1'-azo- bis-1-cyclohexane and 2-, 2'-azo-bis-isobutyric acid alkyl ester; symmetrical diacyl peroxides such as, for example, acetyl, propionyl or butyryl peroxide, benzoyl peroxides substituted by a bromo-, nitro-, methyl- or methoxy group, lauryl peroxides; symmetrical peroxydicarbonates, for example, diethyl, diisopropyl, dicyclohexyl and dibenzoyl peroxydicarbonate; tert-butylperoxy-2-ethylhexanoate, tert-butyl perbenzoate, hydroperoxides such as, for example, tert-butyl hydroperoxide, eumenohydroperoxide; dialkyl peroxides such as dicumyl peroxide; tert-butylcumyl peroxide, di-tert-butyl peroxide or di-tert-amyl peroxide.

Suitable solvents for preparing the polyol component A) are, for example, solvents which can be removed from the aqueous phase of a dispersion by vacuum distillation by continuing the emulsification step and as such are preferably inert to the groups of isosianate Ketones such as acetone and methyl ethyl ketone, and esters such as ethyl acetate and butyl acetate, can be named as examples.

When preparing the polyol binder A) (polyol component A), a reaction medium for the free radical polymerization is first introduced into a polymerization reactor and heated to the desired polymerization temperature. A solvent or a mixture of the aforementioned solvents is provided for use of the polyester component, or also the component b) can, for example, serve as the reaction medium. It is also possible to use any of the solvent combinations and components a) and / or b) as the reaction medium. After the desired polymerization temperature has been reached, the monomer mixture comprises components c) to g) and optionally a) and / or b) and the radical initiator is dispersed in the reaction medium, preferably starting simultaneously . The olefinically unsaturated constituents of the monomer mixture are subjected to free radical copolymerization, wherein the optionally used polyester component a) can be chemically bound to the copolymer as a result of the grafting reactions which can take place to a greater extent or lower under the reaction conditions. The polyester component a) preferably does not have unsaturated double bonds. However, to obtain the specific product properties, it may be appropriate to use polyesters which have polymerizable double bonds and are therefore capable of entering into the copolymerization reactions or grafting reactions.

The polymerization temperature is about 80 to 220 CC, preferably about 90 to 200 ° C and more preferably about 120 to 180 ° C.

Conventional regulators can be used when carrying out polymerization, to regulate the molecular weight of the polyol binders. Mercaptans such as, for example, tert-dodecyl mercaptan, n-dodecyl mercaptan and mercaptoethanol may be mentioned as examples of regulators.

The polymerization generally takes place, in particular if the solvents of the type mentioned above are coused, at a pressure of up to 20 bar in a sealed pressurized polymerization reactor having automatic temperature control. The polymerization can also be carried out at atmospheric pressure if it is operated in a solvent-free manner and using constituents of high boiling monomer which do not cause reflow at temperature below that which is selected for polymerization.

The polyol component A) obtained by the polymerization process described represents valuable binder components for the production of the aqueous powder suspensions according to the invention and forms the substantial polyol constituent, optionally along the components that they contain additional hydroxyl groups such as, for example, other polyesters, polyethers, polyacrylates, polycarbonates and / or polyurethanes, which if necessary can be used in minor proportions along the polyol component A).

The polyisocyanate component B) includes mainly polyisocyanates containing blocked (cyclo) aliphatic isocyanurate groups and optionally iminooxadiazine dione groups and / or biuret groups, as well as optionally urethane and / or allophanate groups. The known (cyclo) aliphatic diisocyanates can be used to prepare the polyisocyanates. Preferably 1-6-diisocyanatohexane (HDI), l-isocyanate-3, 3, 5-trimethyl-5-isocyanato-methyl cyclohexane (isophorone diisocyanate, IPDI), 2,4-cyclohexane and or 2, 6-diisocyanato-l-methyl and 4,4'-diisocyanatodicyclohexyl methane (Desmodur® W, from Bayer AG). Polyisocyanates based on 1,6-hexamethylene diisocyanate, isophorone diisocyanate and Desmodur® W and containing isocyanurate or isocyanurate groups and iminooxadiazine dione groups are particularly preferred for the preparation of component B).

The octan-1, 8-4-isocyanatomethyl diisocyanate can be used as a further major functional polyisocyanate containing no functional groupings apart from the isocyanate groups, for the preparation of the polyisocyanate component B).

To prepare the polyisocyanate component B) the aforementioned polyisocyanates are blocked with conventional blocking agents in a blocking reaction which is known, and optionally modified hydrophilically.

Known monofunctional blocking agents such as malonic acid diethyl ester, ethyl acetoacetate, e-caprolactam, butanone oxime, cyclohexanone oxime, 1, 2, 4-triazole, dimethyl-1,2-triazole, pyrazole or 3,5-dimethyl imidazole are used as blocking agents. Blocking agents which are divided within the temperature range up to 160 ° C, preferably up to 150 ° C, are preferably used. The butatone oxime, cyclohexanone oxime and 3,5-dimethyl pyrazole are preferred, 3-dimethyl pyrazole being particularly preferred.

If the polyisocyanate component is modified hydrophilically, it is affected by methods which are known, ie by reaction of some isocyanate groups with hydroxycarboxylic acids, for example, 2,2-dimethylol propionic acid or 3-hydroxy acid. 2, 2-dimethylpropanoic acid (hydroxypivalic acid) and / or with monofunctional polyethers containing at least 70% by weight of ethylene oxide.

To prepare the crosslinking component B) (polyisocyanate component B), a polyisocyanate is reacted with the blocking agent and / or the hydroxycarboxylic acid and / or the polyether, either sequentially in any order or simultaneously. The polyisocyanates preferably do not become hydrophilic, but only become blocked. It is possible to use both a slight excess and a slight deficit of blocking agent. However, additional processing can also take place if small quantities of unreacted isocyanate groups are still present in the reaction mixture. The reactions take place at a temperature of from 0 to 120 ° C, more preferably 20 to 120 ° C, wherein particularly reactions with hydroxy carboxylic acids are also carried out under mild conditions to prevent reaction with the groups of isocyanate by the carboxyl group.

The reactions can be carried out in a solvent-free manner or in an inert solvent. The reaction preferably takes place in inert solvents, where preferably the aforementioned solvents are used, in particular ethyl acetate, acetone and methyl ethyl ketone.

When the reaction has ended, if the hydrophilic properties have been imparted by a carboxylic acid, the optionally incorporated carboxyl groups are neutralized at least partially with a neutralizing agent. The appropriate neutralizing agents are the alkali metal or alkaline earth metal hydroxides, preferably, however, ammonia and amines such as, for example, triethylamine, triethanolamine, N-methylmorpholine, triethanolamine and most preferably N, N -dimethylethanolamine.

The carboxyl groups optionally present are generally at least 50% neutralized, wherein optionally an excess of neutralizing agent can also be used.

The polyols C) which are optionally used are substances having at least one hydroxyl group. Such substances include but are not limited to the low molecular weight alcohols already described for the preparation of polyester polyols, polyether alcohols having 1 to 6 terminal hydroxyl groups, polyurethane polyols having at least one terminal hydroxyl group, polyesters of e-caprolactone having at least one terminal hydroxyl group and / or polyols having carbonate groups and at least one terminal hydroxyl group.

The additional crosslinking component D) contains substances which, similar to the crosslinking substances B) (polyisocyanate component B), lead to the curing of the coatings according to the invention as a result of the chemical reaction with the hydroxyl groups of the component of polyol A). Amino resins, for example corresponding melamine derivatives, such as alkoxylated melamine resins or melamine-formaldehyde condensation products (for example, FR-A 943 411, "The Chemistry of Organic Filmformers", pp. 235 to 240, John Wiley &Sons Inc., New York 1974), and conventional crosslinking agents, for example epoxies capable of reacting with alcoholic hydroxyl groups, phenolic resins, resole resins, urea resins or guanidine resins or mixtures of they must be named as examples.

To produce the coating compositions according to the invention, the components A), B) and optionally C) to F) as described are mixed together, preferably in solvents which can be removed from the aqueous phase of a dispersion by vacuum distillation. Suitable solvents include but are not limited to acetone and methyl ethyl ketone, and esters such as ethyl acetate and butyl acetate, with ethyl acetate and methyl ethyl ketone being preferred, and methyl ethyl ketone being particularly preferred. Components A) and B) can also naturally be prepared directly in solution and then the subsequent solutions are intermixed. Components A) and B) are more preferably prepared in methyl ethyl ketone and then mixed.

If so required and previously unaffected, the additional polyfunctional crosslinking substances, neutralizing agents, small amounts of external emulsifiers, as well as additional auxiliary substances and additives such as, for example, thickeners, flow promoters, light stabilizers and / or catalysts, optionally they can be introduced into the subsequent solution of A) and B).

Then the organic solution is mixed with water to produce the aqueous suspensions. This takes place either by the direct dispersion process, where the organic phase is dispersed in the aqueous phase, or by the phase inversion process, where a water-in-oil emulsion initially present is converted into an oil emulsion. in water with the addition of a dispersion device having a dispersion powder related to the high volume. The later may include for example, cage type agitators, solvents, rotor / stator type mixers, pressure relief type nozzles, preferably jet dispersers, wherein the dispersion powder related to the volume for the dispersion process is approximately 1x10 to 9.8x10000 W / cm3, preferably 1x10 to 1x10000 W / cm3 and more preferably 1x10 to 1x1000 W / cm3. The average particle size of the aqueous dispersion or suspension particles is about 0.05 to 10 μm, preferably 0.1 to 5 μm, in particular 0.15 to 2.5 μm and more preferably 0.2 to 1.5 μm.

In order to obtain the specific particle size distributors, it may be practical or advantageous to carry out the dispersion in a plurality of stages to a powder related to the defined volume.

In principle, it may be an advantage to prepare a preemulsion by means of a stirrer or solvent and then to supply the preemulsion subsequent to the jet disperser, before the dispersing operation takes place in the jet disperser. When the dispersions or emulsions are produced, an amount of water is used in such a way that dispersions or emulsions of 20 to 60% by weight, preferably 30 to 60% by weight and more preferably 35 to 60%, result. by weight of the coating compositions according to the invention. When the addition of water is completed, the solvent is preferably removed by vacuum distillation.

A dispersion can take place within a wide range of temperature, both at a low temperature, for example from 0 to 20 ° C, and at a higher temperature which can markedly exceed the boiling point of the polymer mixture, for example from 100 to 150 ° C.

A process which, however, it will also be possible in principle to produce the aqueous dispersions or emulsions include mixing, with an aqueous solution of a neutralization agent of the named type, mixtures of A) and B) having carboxyl and hydroxyl groups free and blocked isocyanate groups, optionally in the form of an organic solution in one of the solvents named by way of example, such that the neutralization and the dissolution or dispersion operations take place as a single step.

The mixing ratio of the polyol component A) to the blocked polyisocyanate component B) is selected such that the equivalent ratio of the blocked isocyanate groups of component B) to the alcoholic hydroxyl groups of component A) is about 0.5: 1 to 2: 1, preferably about 0.7: 1 to 1.5: 1 and more preferably about 0.8: 1 to 1.2: 1.

The additional polyfunctional hydroxyl components C), polyfunctional crosslinking agents D), external emulsifiers E) and conventional additives F) can be added to the aqueous binder mixture, but also to the individual components A) and B) before they are combined or even during the preparation, or to the mixture of A) and B) before or after the dispersion.

The coating compositions according to the invention thus produced can be applied in the form of a layer or multilayer to heat resistant substrates by methods which are known per se, for example by spraying, brushing, dip coating, Flood or by roller or blade.

The coatings are obtained, for example from metal, plastic material, wood or glass, by curing the coating from 80 to 220 ° C, preferably 90 to 180 ° C and more preferably 100 to 160 ° C.

The binders according to the invention are preferably suitable for producing coatings and finishes on optionally pre-prepared steel sheets and optionally filled and with a base layer or other metal foils such as are used, for example, in the manufacture of automotive or aviation components, machines, cylinders, boards or containers. The coating films generally have a dry film thickness from 0.01 to 0.3 mm.

The markedly lower solvent content is a remarkable advantage over systems that have water. Due to the comparison with conventional water-borne coatings, the markedly lower organic co-solvent content and the higher application certainty which results from the larger application window are advantageous. The substantially reduced tendency to boil and a resistance to flexion are also noteworthy.

The remarkable superiority over conventional powder coatings is provided by the good flow at markedly reduced film thicknesses, the possibility of application using the wet coating plant of an existing package, the greater facility of cleaning of the plant and the absence of interruptions in the coating line due to fine dispersed powders.

The invention is further illustrated but is not intended to be limited by the following examples, in which all parts and percentages are by weight unless otherwise indicated.

Examples General directions for preparing a polyester polyacrylate polyol or polyacrylate polyol Polyol components (Al and A2) The polyol components Al and A2 are prepared from three compositions designated below as "Part I", "Part II", "Part III".

Part I is placed in a special 10 liter pressurized steel reactor fixed with stirring, cooling and heating equipment and with electronic temperature control, and heated up to the reaction temperature. Then starting simultaneously, Part II (addition for a total period of 3 hours) and Part III (addition for a total period of 3.5 hours) are dispersed in a sealed reactor with the contents of the reactor at virtually constant temperature (± 2 C) . After the addition of Part III, the post-treatment takes place at the polymerization temperature for 1 hour. Then the resin solution which results is cooled to 30 ° C and filtered.

The reaction temperatures and the compositions of Parts I to III are shown in Table 1, together with the characteristic data of the products obtained.

Start material The polyester: the polyester polyol of 98 mg KOH / g of hydroxyl value and 1.5 mg KOH / g of acid value, is prepared by reacting 22.07 parts by weight of 2-ethylhexanoic acid, 30.29 parts by weight of trimethylolpropane, 12.67 parts by weight of neopentyl glycol, 32.24 parts by weight of hexahydrophthalic acid anhydride and 12.29 parts by weight of adipic acid.

Table I: The polyols Al and A2 of the coating compositions according to the invention (the amounts are given in g) Preparation of the crosslinking component B) (Blocked polyisocyanates Bl and B2) Polyisocyanate 1 1332 g of isophorone diisocyanate (IPDI) is placed under nitrogen in a 2-liter 4-necked flask equipped with a stirrer, gas inlet pipe, internal thermometer, dispersion funnel and reflux condenser, and heated to 70 ° C. 15 ml of a 5 wt% solution of trimethylammonium hydroxide of 2-hydroxypropyl in 2-ethyl-l, 3-hexanediol / methanol (6: 1 parts by weight) is dispersed in the flask slowly and uniformly from of a dispersion funnel within 45 minutes. The temperature increases up to 88 ° C since it takes place (it must not exceed 90 ° C because the trimerization is not specific to excessive temperatures and leads to higher final product viscosities). After the dispersion is finished, the stirring is carried out at 80 ° C until the reaction mixture reaches an NCO content of 30.6%. Then the process is stopped by the rapid addition of 0.36 g (70 molar ppm) of a 25% solution of dibutyl phosphate in IPDI. The IPDI monomer is removed by thin film distillation. A 44% yield of a clear, colorless clear resin is virtually obtained, which dissolves at a concentration of 70% in methyl ethyl ketone. The viscosity of the solution at 23 ° C is about 300 mPa.s, the isocyanate content is 11.8%, and the monomer content of free IPDI is about 0.18%.

Polyisocyanate 2 ™ Desmodur N 3300 (Bayer AG), solids content: 100%; viscosity at 23 ° C: 3500 mPa.s; Isocyanate content 21.8%.

Preparation of a blocked polyisocyanate Bl 500 g of Polyisocyanate 1 are placed in a 1-liter 3-necked flask equipped with stirrer, internal thermometer and reflux condenser, and heated to 60 ° C. 134.8 g of 3,5-dimethylpyrazole is added in portions, with stirring, and then stirring is continued at 60 ° C until the additional isocyanate band is observable in the IR spectrum.Preparation of a blocked polyisocyanate B2 150 g of Methyl Ethyl Ketone are added to 350 g of Desmodur N 3300 in a 1-liter 3-necked flask equipped with a stirrer, internal thermometer and reflux condenser, and the bath is heated to 50 ° C, with stirring. Then 174.4 g of 3,5-dimethylpyrazole are added in portions, and the stirring takes place at 50 ° C until no additional isocyanate band is observable in the IR spectrum.

Example 1 Preparation of aqueous dispersions which are preferably dried in a dusty manner Dispersion 1 701. 6 g of the Polyester Polyacrylate Polyester Al and 453.4 g of the blocked polyisocyanate Bl are dissolved in 1464.4 g of methyl ethyl ketone (MEK), and 7.1 g of the dimethylethanolamine are added as the neutralizing agent. Then the following amounts of additives are added: 6.5 g of Byk 348 (flow promoter, Byk-Chemie) and 10.5 g of WN emulsifier (emulsifier of Bayer AG).

A water-in-oil emulsion is prepared from 2654 g of the binder solution, neutralizing agent and additive in MEK by intensive intermixing with 1613.2 g of water by means of a solvent, and then converted by phase inversion into a oil-in-water emulsion passing through a high-pressure jet disperser (0.5 bar) according to EP 0 101 007. The MEK is distilled under vacuum, and the post-stabilization takes place with 10.5 g of WN emulsifier. A polymer dispersion having the following characteristic data results: Flow time (4 ISO cuvettes, 23 ° C): 15 sec. Solids content: 50% Average particle size (laser correlation spectroscopy) 0.90 μm Vitreous transition temperature: 62 Dispersion 2 1337. 6 g of the polyacrylate polyol A2 and 1051.9 g of the blocked polyisocyanate Bl are dissolved in 2033 g of methyl ethyl ketone (MEK), and 11.7 g of the dimethylethanolamine are added as a neutralizing agent. Then add the following amounts of additives: 17.4 g of Byk 348 (flow promoter, by Byk-Chemie) and 52.3 g of emulsifier NP 30 (emulsifier of Bayer AG).

A water-in-oil emulsion is prepared from 4000 g of the binder solution, neutralizing agent and additives in MEK by intensive intermixing with 2154 g of water by means of a solvent, and then converted by phase inversion into a oil in water emulsion passing through a high pressure jet disperser (1.0 bar) according to EP 0 101 007. The MEK is distilled under vacuum. After filtration (10 μm) a polymer dispersion results which has the following characteristic data: Flow time (4 ISO cuvettes, 23 ° C): 15 sec. Solids content: 49.7% Average particle size (laser correlation spectroscopy) 0.51 μm Vitreous transition temperature: 56 ° C Dispersion 3 1812. 0 g of the polyacrylate polyol A2, 911.4 g of blocked polyisocyanate Bl and 372.1 g of the blocked polyisocyanate B2 are dissolved in 2620 g of methyl ethyl ketone (MEK), and 16.0 g of the dimethylethanolamine are added as a neutralizing agent. The following amounts of additives are then added: 22.4 g of Byk 348 (flow promoter, by Byk-Chemie) and 67.4 g of WN emulsifier (emulsifier of Bayer AG).

A water-in-oil emulsion is prepared from 5000 g of the binder solution, neutralizing agent and additives in MEK by intensive intermixing with 2618 g of water by means of a solvent, and then converted by phase inversion into a oil in water emulsion passing through a high pressure jet disperser (1.0 bar) according to EP 0 101 007. The MEK is distilled under vacuum. After filtration (10 μm) a polymer dispersion results which has the following characteristic data: Flow time (4 ISO cuvettes, 23 ° C): 15 sec. Solids content: 50.6% Average particle size (laser correlation spectroscopy) 0.33 μm Vitreous transition temperature: 45 ° C Example 2 Applications and properties The application and properties of the movie. Clear coatings are described by means of an example.

The following additives shown in Table 2 are added to the coating dispersions 1 to 3, which are adjusted to the viscosity of application: Table 2 When the coating dispersions 1 to 3, formulated in this manner, are applied to a surface and dried at room temperature, a powdery surface is formed which can be easily removed with water.

When the aqueous dispersions are protected immediately after application, a high gloss coating film having good flow and good resistance to water, organic and chemical solvents is obtained.

The light coatings produced are applied by means of a spray gun with conventional commercial air mixture to a metal sheet precoated with an aqueous cathodic electrodeposition coating, an aqueous filler film and an aqueous black first-hand film, as used conventionally in original automotive finishes.

Evaporation is left at room temperature for 2 minutes after application, and then the leaves are cured immediately at 150 ° C for 30 minutes. The coating properties of the clear coating film based on dispersions 1 to 3 are shown in Table 3 below.

Table 3 1) n.o.e. = unobservable effect 2) 0 = best value (unobservable effect), 5 = bad value (dissolved film) 3) gradient oven method: The surface of the coating is exposed to the indicated substance at different temperatures in the gradient oven (from Byk-Gardner) for 30 minutes. The surface of the coating is then cleaned, followed by visual evaluation. The deterioration is expressed as ° C.

First value: first visible change as a result of swelling. Second value: first visible change as a result of the chemical attack.

Although the invention has been described in detail in the foregoing for the purpose of illustration, it is understood that such detail is only for that purpose and those variations can be made here by those skilled in the art without departing from the scope of the invention.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims (19)

1. An aqueous coating composition, characterized in that it comprises: A) a polyol component comprising a member selected from the group consisting of polyester, polyacrylate and polyester polyacrylate polyols, the polyol component having a hydroxyl group content of from about 1.0 to about 6.0% by weight, a group content carboxyl from about 0 to about 1.5% by weight, a weight average molecular weight of 2000 to 50000 and a vitreous transition temperature that is greater than or equal to 30 ° C; a polysiocyanate component comprising a member selected from the group consisting of aliphatic isocyanates and cycloaliphatic isocyanates having a blocked isocyanate group content of from about 10.0 to about 25.0% by weight.

2. The composition according to claim 1, characterized in that the composition further comprises a component selected from the group consisting of external emulsifiers, neutralizing agents, catalysts, auxiliary substances, degassing agents, flow promoters, radical interceptors, antioxidants, absorbers of ultraviolet UV light, thickeners, solvents and biocides.

3. The composition according to claim 1, characterized in that the polyol component comprises: a) from 0 to 100 parts by weight of a polyester component comprising at least one polyester polyol having a hydroxyl value from about 20 to about 240 mg KOH / g an acid value of less than 12 mg KOH / g a vitreous transition temperature from about -40 to 80 ° C, b) from 0 to 15 parts by weight of an olefinically unsaturated ester component which comprises at least one ester of di (cislo) alkyl of an acid maleide having 1 to 12 carbon atoms in the radical (only) alkyl, c) from 0 to 70 parts by weight of esters of (cislo) alkyl of asidid and / or metasylism comprising 1 to 18 carbon atoms in the radical (cyclo) alkyl, d) from 0 to 50 parts by weight of unsaturated olefinically aromatic monomers, e) from 0 to 50 parts by weight of esters of hydroxyalkyl or asidyl and / or methacrylic acid having 2 to 6 carbon atoms in the hydroxyalkyl radical, and / or reaction products thereof with e-caprolastone having a weight molecular weight of 500, as well as addition products of hard grinding and / or metasylism and monoepoxy coatings, the suals can also be generated in situ during the polymerization of free radisal, f) from 0 to 5 parts by weight of olefinically unsaturated carboxylic acids, and g) from 0 to 30 parts by weight of additional copolymerizable olefinically unsaturated compounds where the sum of the parts by weight of the components a up to g is 100.

4. The composition according to claim 1, characterized in that the polyisocyanate component comprises a polyisocyanate selected from the group of polyisocyanates which are blocked aliphatic isosanurate groups, blocked cycloisocyanurate groups, iminooxadiazine dione groups, biuret groups, urethane, and allophanate.

5. The somiposity of the deformation to claim 1, characterized in that the step of forming the aqueous dispersion to form a dispersion is an average particle size ranging from about 0.05 to about 10 μm.

6. The composition of the sonformity to claim 1, characterized in that the composition is solvent-free.

7. The deposition according to claim 1, which is sarasterized by the polyol component and the polysiosiana component, is presented at a melting propulsion that ters from about 0.5: 1 to 2: 1.

8. A powder coating, which is sarasterized because it is formed by passing the suspension of claim 1 at room temperature.

9. The composition according to claim 1, sarasterized because the somposision is made by combining (i) a polyol component which includes a member of the group consisting of polyester, polyacrylate and polyester polyasrilate polyols having a hydroxyl group content of from about 1.0 to about 6.0% by weight, a sarboxyl group containing from about 0 to about 1.5% by weight, a weight average molecular weight of 2000 to 50000 and a glass transition temperature that is greater than or equal to 30 ° C; and (ii) a polyisocyanate component comprising a member selected from the group consisting of aliphatic isocyanates and isocyanate isocyanates having a blocked isosiana group content from about 10.0 to about 25.0% by weight; they are water to form a somposision of asuosa coating.

10. A method of elaboration of a somposision of asuosa coating, sarasterizado because somprende to combine (i) a polyol component selected from the group consisting of polyester, polyacrylate and polyester polyacrylate polyols having a hydroxyl group content of from about 1.0 to about 6.0% by weight, a carboxyl group content from about 0 to about 1.5 % by weight, a weight average molecular weight of 2000 to 50000 and a glass transition temperature that is greater than or equal to 30 ° C; Y (ii) a polyisocyanate component comprising a member selected from the group consisting of aliphatic isocyanates and cycloaliphatic isocyanates having a blocked isocyanate group content from about 10.0 to about 25.0% by weight; they are water to form a sombossion of asuosa coating.

11. The method of soundness to claim 10, which is sarasterized because the combination step of the polyol component and the polyisonate component is further subdued, is a component selected from the group consisting of neutralizing agents, catalysts, excipients, degassing agents, promoters of flow, radical interceptors, antioxidants, ultraviolet UV absorbers, thickeners, solvents and biosides.

12. The method of resilience to the claim 10, sarasterized in that the polyol and the polyisosyanate somatomers are combined to form an organic phase and the deposition of the asuous coating is formed by dispersing the organelle phase in the asuous phase by a diresto dispersion process.

13. The sonicity method according to claim 10, characterized in that the polyol and the polyisocyanate components are combined with water to form a water-in-oil emulsion and the aqueous coating composition is formed by converting the water-in-oil emulsion to an oil emulsion. in water by a phase inversion procedure.

14. The method according to claim 12, characterized in that the deposition of asuosa coating is formed by means of a dispersion device having a dispersion powder related to the volume of 1x10 to 9.8x10000 W / cm3.

15. The method of soundness to the claim 13, characterized in that the asuosa coating composition is formed by means of a dispersion device having a dispersion powder related to the volume of 1x10 up to 9. 8x10000 W / cm3.

16. The method according to claim 14, characterized in that the dispersion device has a pressure relief homogenization nozzle.

17. The method according to claim 15, characterized in that the dispersion device has a homogenization nozzle type pressure relief.

18. A method to make a coating, sarasterized because it includes the steps of: a) applying the asuosa composition of the claim 1 on a substrate, b) batching the aqueous coating composition in a powdery manner to form a powder at room temperature, and c) heating the powder to a temperature that is high enough to form a coating.

19. The method according to claim 18, characterized in that the dusting step of the powder comprises protecting the powder at a temperature ranging from about 80 to about 220 ° C.